To support its ongoing monitoring program of therapeutic and diagnostic allergen preparations, LIB has initiated a multifaceted study of the factors that enhance or diminish the immune responses to allergens. These include: 1. DNA vaccines. DNA vaccines are plasmids that encode target antigens, the injection of which can raise significant Th1 and Th2 immune responses to those antigens. Previous studies have shown that DNA vaccines can down-regulate IgE responses. Dr. Slater and Ms. Paupore have generated a DNA vaccine for Hev b 5, and have demonstrated the widespread dissemination of the encoded antigen after injection. 2. LPS effect on allergen responses. LPS is a common contaminant in latex gloves and in the environment. Dr. Slater and Ms. Paupore have demonstrated that LPS increases murine IgG and IgE responses to recombinant Hev b 5. 3. Hev b 5 epitope study. Hev b 5 is an important allergen in Hevea latex products. The identification of relevant epitopes can be used as a toll for the immunomodulation of responses to latex allergens. We have identified putative B-cell and T-cell epitopes of Hev b 5 in BALB/c mice. 4. Cross-reactive allergens in foods and latex. Cross-reactivity among allergens can provide important insights into the relationships of structure to immunogenicity. Dr. Hsieh characterized and sequenced a major allergen in avocado, Prs a 1, which has chitinase activity an cross-reacts with the latex allergen Hev b 6. Dr. Poley has initiated studies to identify the effect of pre-sensitization with cross-reactive fruits on latex immunity.